1. Field of the Invention
The invention relates to a hydrotherapy jet system and more particularly, to the design of pulsating hydrotherapy jets.
2. Description of the Related Art
Various hydrotherapy jets have been developed in the past, for use in spas, hot tubs and bath tubs, that discharge an aerated stream of water through a variety of discharge nozzles. In general, such jets produce a constant flow stream which provides a good therapeutic effect. However, in an attempt to enhance the therapeutic effect, several systems have been designed that produce a pulsating flow. These systems have met with varying degrees of success as they often require additional or larger components, which increase system cost and add complexity, or they generate unwanted pressure losses, thus requiring a larger water pump then would otherwise be required.
One prior art approach has been to use mechanical devices to pulse the water flowing to an individual jet or a series of jets. An example of such a system is described in U.S. Pat. No. 4,320,541 to John S. Neenan. In this approach, a series of mechanical blocking devices are used to intermittently block and unblock the flow stream. As the flow stream is unblocked, a pulse of water is sent to the jet and ultimately to the user. While this approach does provide a pulsating effect, the blocking and unblocking of the flow stream causes abrupt pressure increases, imposing strain on spa systems. Aside from these drawbacks, such systems require additional components which add complexity, cost and weight. In addition, since the pulsation effect is generated away from the jet, the pulsed flow stream experiences pressure loss, resulting in a decreased pulsation effect being felt at the jet exit.
In an alternate approach, rather than using mechanical devices to generate a pulsated flow, a hydraulic pumping device is utilized. In such a system, pulsation is produced by a distribution valve which houses a rotor that is rotated by inlet water flow and distributes the inlet water to a series of outlets which are connected to the individual jets. The rotor is formed with a groove which sequentially aligns the water outlets to the water inlet. Since each outlet is periodically connected to and disconnected from the inlet, the water is supplied to each jet in a pulsating or chopped manner. Examples of this type of system are given in U.S. Pat. Nos. 5,444,879 and 5,457,825 to Michael D. Holtsnider and assigned to B&S Plastics, Inc., the assignee of the present invention.
While the hydraulic systems do provide a degree of pulsation, they too suffer from many of the same problems as the mechanical systems. For example, as the pulsation effect is generated away from the jet, the pulsed flow stream experiences pressure loss, resulting in a reduced pulsation effect at the jet, and like the mechanical systems, the additional componentry adds complexity, cost and weight to the system. Also, a larger water pump may be required to provide the additional energy necessary to rotate the rotor and to compensate for additional pressure losses.
To overcome the drawbacks associated with mechanical and hydraulic pulsed systems, pulsation systems have been designed that do not require mechanical devices or hydraulic distribution systems. Such systems generally have individual pulsation mechanisms located within the individual jets. For example, as shown in the Waterway "1997 Product Catalog", page 1, Deluxe and Octagon series pulsator jet, and U.S. Pat. No. 5,657,496 to Corb et al., also assigned to B&S Plastics, Inc., the individual jets contain rotational devices commonly called eyeballs. The eyeballs have one or more water conduits which discharge water flowing through the jet into the spa or tub. The conduits are angled to cause the eyeball to rotate and distribute the flow steam in a circular pattern. This circular distribution provides, to some degree, the sensation of a pulsed flow as the flow stream interacts with a specific point on the body is periodic fashion. However, this is not truly a pulsed flow since the user actually experiences a continual flow stream but yet in a circular pattern.
Attempts have been made to produce a jet that would produce a true pulsed flow. To this end several designs have been developed in which pulsation is created at the jet itself. In these systems, the flow stream at the jet is blocked periodically to create the sensation of a pulsed flow. See Waterway "1997 Product Catalog", page 1, Standard Poly Jets whirly and pulsator jets, and U.S. Pat. No. 4,508,665 to Spinnett. While both the Waterway and Spinnett jet designs do in fact produce a pulsed flow, the pulsing is created by blocking the flow stream exiting the rotary member as it rotates past a blocking device. When the flow stream comes in contact with the blocking member the flow is temporarily interrupted or halted, thus a pulsed flow. The pulsed flow generated is circular or spiral in nature, moving from one zone to another in a sequential manner. The blocking however creates an undesirable backflow into the jet, causing strain on the spa systems and ultimately lowering its efficiency. In addition, the Spinnett design requires multiple deflections of the flow stream as it passes through the jet, causing pressure losses and lowering the system efficiency.